Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

298
FXUS63 KLOT 270751
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
251 AM CDT Wed May 27 2026

.KEY MESSAGES...

- Generally warm and dry conditions are expected through early
  next week.

- Daily lake breezes will keep temperatures cooler near the
  lakeshore with backdoor cold fronts bringing cooler
  conditions farther inland Thursday and again over the weekend.

&&

.DISCUSSION...
Issued at 251 AM CDT Wed May 27 2026

The local area remains situated between two separate
disturbances early this morning. The system to our south
continues to very gradually lift northeast across the Ohio
Valley and may bring a few showers/sprinkles to the far southern
forecast area early this morning (mainly south of a Paxton to
Rensselaer line). These showers will be encountering an
increasingly dry airmass so a sharp gradient is expected along
its northern periphery, keeping the rest of the area dry.
Meanwhile a stalled surface boundary draped across Wisconsin
paired with a weak mid-level wave/vort will likely lead to
scattered shower and storm development well to our north this
afternoon. These storms may attempt to propagate south toward
northern Illinois late this afternoon into early evening. They
will be encountering the much drier airmass in place here
locally and are expected to erode prior to reaching the state
line.

Ample sunshine and fairly deep mixing will support temperatures
warming into the mid to upper 80s today for inland areas, with
lower 70s possible along the lakeshore before a lake breeze
moves inland midday dropping temperatures back into the 60s.

The aforementioned stalled surface boundary is expected to
eventually dive southwest as a backdoor cold front across the
area into this evening. In addition to steadily falling
temperatures, winds will become increasingly gusty out of the
northeast in its wake, leading to quickly building waves at area
beaches. How early the front arrives remains somewhat
uncertain but is generally expected sometime between ~6-9 PM,
likely dependent on convective trends in Wisconsin later today.
Will have to monitor observations closely through the afternoon
in case the start time of the Beach Hazard Statement needs to
to be moved up an hour or two. High waves and rip currents then
likely persist through Thursday and potentially into Thursday
night.

Ensembles continue to support an expansive area of surface high
pressure setting up across the region paired with high
amplitude ridging extending well into Canada. This increases
confidence in continued warm and rain-free conditions across the
region into the first week of June. The general position of
high pressure will be favorable for onshore winds most days,
which paired with daily reinforcing lake breezes will keep
temperatures cooler near the lakeshore. There remains the
potential for additional backdoor cold fronts at times over the
weekend into early next week leading to cooler more seasonable
conditions extending farther inland at times.

Petr

&&

.AVIATION /06Z TAFS THROUGH 12Z THURSDAY/...
Issued at 1226 AM CDT Wed May 27 2026

Dry and VFR conditions are forecast through the TAF window.
Winds will be light and variable overnight before becoming more
consistently out of the northeast after daybreak. As a dry
backdoor front moves south down western Lake Michigan after
00Z, winds will remain out of the northeast but gusts around 20
knots are expected through Thursday morning.

DK

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Air Quality Alert until 6 AM CDT Thursday for ILZ005-ILZ006-
     ILZ012-ILZ013-ILZ020-ILZ021-ILZ103-ILZ104-ILZ105-ILZ106-
     ILZ107-ILZ108.

     Beach Hazards Statement from this evening through late
     Thursday night for ILZ006-ILZ103-ILZ104.

IN...Air Quality Alert until midnight CDT tonight for INZ001-INZ002-
     INZ010-INZ011.

     Beach Hazards Statement from late tonight through late
     Thursday night for INZ001-INZ002.

LM...Small Craft Advisory from 10 PM this evening to 10 PM CDT
     Thursday for the IL nearshore waters.

     Small Craft Advisory from 4 AM Thursday to 1 AM CDT Friday for
     the IN nearshore waters.

&&

$$

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